The present invention relates to metallographic molding apparatus and particularly to improved closure means for a molding chamber associated therewith.
In the preparation of metallographic specimens for inspection, a small metallographic specimen is typically encased in a thermoplastic or thermoset material and subsequently ground and polished for examination by a microscope. In order to encapsulate the metallographic specimen, relatively small but high pressure and temperature molding tabletop sized molding devices are employed. With such systems, it is desirable to provide easy access to the mold cavity so that the operator can easily operate the system and yet have the apparatus be foolproof to assure the mold cavity is lockably sealed to prevent leakage during molding or failure of the device during the pressure molding cycle of operation. One problem with such systems has been the difficulty in removing the encapsulated metallographic specimen due to the thermoplastic or thermoset material oozing between the piston and cylinder wall during the molding cycle. This flash, as it is referred to, frequently makes it difficult to eject the specimen from the apparatus once molded.